/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.tomcat.util.net.jsse;

import javax.net.ssl.SSLEngine;
import javax.net.ssl.X509ExtendedKeyManager;
import javax.net.ssl.X509KeyManager;
import java.net.Socket;
import java.security.Principal;
import java.security.PrivateKey;
import java.security.cert.X509Certificate;

/**
 * X509KeyManager which allows selection of a specific keypair and certificate
 * chain (identified by their keystore alias name) to be used by the server to
 * authenticate itself to SSL clients.
 *
 * @author Jan Luehe
 */
public final class JSSEKeyManager extends X509ExtendedKeyManager {

	private X509KeyManager delegate;
	private String serverKeyAlias;

	/**
	 * Constructor.
	 *
	 * @param mgr            The X509KeyManager used as a delegate
	 * @param serverKeyAlias The alias name of the server's keypair and
	 *                       supporting certificate chain
	 */
	public JSSEKeyManager(X509KeyManager mgr, String serverKeyAlias) {
		super();
		this.delegate = mgr;
		this.serverKeyAlias = serverKeyAlias;
	}

	/**
	 * Choose an alias to authenticate the client side of a secure socket,
	 * given the public key type and the list of certificate issuer authorities
	 * recognized by the peer (if any).
	 *
	 * @param keyType The key algorithm type name(s), ordered with the
	 *                most-preferred key type first
	 * @param issuers The list of acceptable CA issuer subject names, or null
	 *                if it does not matter which issuers are used
	 * @param socket  The socket to be used for this connection. This parameter
	 *                can be null, in which case this method will return the most generic
	 *                alias to use
	 * @return The alias name for the desired key, or null if there are no
	 * matches
	 */
	@Override
	public String chooseClientAlias(String[] keyType, Principal[] issuers,
	                                Socket socket) {
		return delegate.chooseClientAlias(keyType, issuers, socket);
	}

	/**
	 * Returns this key manager's server key alias that was provided in the
	 * constructor.
	 *
	 * @param keyType Ignored
	 * @param issuers Ignored
	 * @param socket  Ignored
	 * @return Alias name for the desired key
	 */
	@Override
	public String chooseServerAlias(String keyType, Principal[] issuers,
	                                Socket socket) {
		return serverKeyAlias;
	}

	/**
	 * Returns the certificate chain associated with the given alias.
	 *
	 * @param alias The alias name
	 * @return Certificate chain (ordered with the user's certificate first
	 * and the root certificate authority last), or null if the alias can't be
	 * found
	 */
	@Override
	public X509Certificate[] getCertificateChain(String alias) {
		return delegate.getCertificateChain(alias);
	}

	/**
	 * Get the matching aliases for authenticating the client side of a secure
	 * socket, given the public key type and the list of certificate issuer
	 * authorities recognized by the peer (if any).
	 *
	 * @param keyType The key algorithm type name
	 * @param issuers The list of acceptable CA issuer subject names, or null
	 *                if it does not matter which issuers are used
	 * @return Array of the matching alias names, or null if there were no
	 * matches
	 */
	@Override
	public String[] getClientAliases(String keyType, Principal[] issuers) {
		return delegate.getClientAliases(keyType, issuers);
	}

	/**
	 * Get the matching aliases for authenticating the server side of a secure
	 * socket, given the public key type and the list of certificate issuer
	 * authorities recognized by the peer (if any).
	 *
	 * @param keyType The key algorithm type name
	 * @param issuers The list of acceptable CA issuer subject names, or null
	 *                if it does not matter which issuers are used
	 * @return Array of the matching alias names, or null if there were no
	 * matches
	 */
	@Override
	public String[] getServerAliases(String keyType, Principal[] issuers) {
		return delegate.getServerAliases(keyType, issuers);
	}

	/**
	 * Returns the key associated with the given alias.
	 *
	 * @param alias The alias name
	 * @return The requested key, or null if the alias can't be found
	 */
	@Override
	public PrivateKey getPrivateKey(String alias) {
		return delegate.getPrivateKey(alias);
	}

	/**
	 * Choose an alias to authenticate the client side of a secure socket,
	 * given the public key type and the list of certificate issuer authorities
	 * recognized by the peer (if any).
	 *
	 * @param keyType The key algorithm type name(s), ordered with the
	 *                most-preferred key type first
	 * @param issuers The list of acceptable CA issuer subject names, or null
	 *                if it does not matter which issuers are used
	 * @param engine  Ignored
	 * @return The alias name for the desired key, or null if there are no
	 * matches
	 */
	@Override
	public String chooseEngineClientAlias(String[] keyType, Principal[] issuers,
	                                      SSLEngine engine) {
		return delegate.chooseClientAlias(keyType, issuers, null);
	}

	/**
	 * Returns this key manager's server key alias that was provided in the
	 * constructor.
	 *
	 * @param keyType Ignored
	 * @param issuers Ignored
	 * @param engine  Ignored
	 * @return Alias name for the desired key
	 */
	@Override
	public String chooseEngineServerAlias(String keyType, Principal[] issuers,
	                                      SSLEngine engine) {
		return serverKeyAlias;
	}
}
